Diphenyl ether herbicides are commonly applied POST in soybean to control weeds late in the growing season that have not been controlled by other previous weed management tactics. These “rescue” applications can occur during reproductive soybean growth. The effect of these herbicides on the developing flowers and pods is not known. Field research studies were conducted over 3 yr to determine how soybean flowers and developing pods respond to fomesafen, acifluorfen, and lactofen when applied at R1, R3, and R5 growth stages. Flower and pod counts in the nontreated check showed an increase (17.1, 5.8, and 2.21 at R1, R3, and R5 stage, respectively) and were statistically the same as the herbicide treatments 1 wk after treatment. Fomesafen, acifluorfen, and lactofen applied at 395, 420, and 219 g ai ha^-1 at R1, R3, and R5 stage had no negative impact on soybean flowers and developing pods when compared to the nontreated check. No significant differences were observed in soybean yield between any treatments in all site-years of the study.

Nomenclature: Fomesafen; acifluorfen; lactofen; soybean, Glycine max (L.) Merr.